In the past, various methods and apparatus were employed to effect indexing of work-pieces, such as a dynamoelectric machine for instance, between work positions at a work station and/or between a plurality of work stations for performing various manufacturing operations on the indexed work-pieces. Past mechanical indexing apparatus for effecting a "two stop" or 180.degree. index was usually accomplished by oscillation instead of indexing and consists of a simple rack and pinion mechanism driven by a servo motor, such as an air or hydraulic actuating cylinder or the like; however, one of the disadvantageous or undesirable features of this type of apparatus is believed to be that it produced an output movement having very poor acceleration and velocity characteristics. For instance, after the initial acceleration of the actuating cylinder during its stroke to its speed setting, the actuating cylinder thereafter was moved at a constant velocity for most of the rest of its stroke, and at the end of its stroke, the actuating cylinder was stopped by an internal cushioning device and/or an external dash pot arrangement prior to the reversal of the stroke. Furthermore, it often happened that the driven load on the output shaft of the actuating cylinder was quite large in relation to the actuating cylinder size; and such out-sized load thereupon became the driver, i.e., once it was in motion, requiring the internal cushioning device and/or external dash pot arrangement to stop not just the force of the actuating cylinder rod but the entire load being index which, of course, was also a disadvantageous or undesirable feature. In addition to the foregoing, another disadvantageous or undesirable feature of the past mechanical indexing apparatus is believed to be that minor variations in the driven load thereof, such as differing fixtures, part sizes, frictions, etc., resulted in irratic output motion of the actuating cylinder shaft which was especially noticeable or prevalent at the end of its stroke. Of course, efforts have been made in the past to overcome these deficiencies by increasing the size of the actuating cylinder and component parts associated therewith as well as increasing the stroke of the actuating cylinder; however, these changes merely resulted in a rather bulky apparatus without appreciably correcting or affecting the aforementioned undesirable uniform velocity with high accelerations and decelerations of the output shaft. It may also be noted that geneva gear mechanisms are not capable of indexing an output shaft 180.degree..
U.S. Pat. Nos. 65,981, 595,732 and 3,459,056 each concern the conversion of non-harmonic acceleration of substantially linear reciprocal movement into generally harmonic acceleration; however, while these patents may have at least some advantageous features, one of the disadvantageous or undesirable features thereof is believed to be that each requires dual inputs or drivers to effect the aforementioned conversion as well as a multiplicity linkage which are not only costly but also difficult to adjust and to maintain in the proper adjustment.
Also in the past, several different methods of assembling dynamoelectric machines have been utilized to effect proper radial and axial alignment of the rotatable assembly, stator and end frames of the dynamoelectric machine. For example, through-bolts have been used to interconnect the stator and end plates of a dynamoelectric machine with the rotatable assembly thereof journaled in the end plates; however, one of the disadvantageous or undesirable features of this construction is believed to be that rather close tolerances were required to attain proper alignment of the dynamoelectric machine components, and maintaining close tolerances manifestly results in increased machining and assembly costs of manufacture. Another past method of assembling dynamoelectric machines was to employ an oversized dummy rotatable assembly to effect the necessary alignment between the stator and end plate and thereafter substitute an actual rotatable assembly for the dummy rotatable assembly; however, one of the disadvantageous or undesirable features of this method of construction is believed to be that it was limited to "unit bearing" type machines wherein the rotatable assembly is supported in only one end frame. As a result, this method was unavailable for use in the greater majority of dynamoelectric machines wherein the rotatable assembly is supported in oppositely disposed end frames.
In U.S. Pat. No. 3,165,816 shims were disposed between the rotatable assembly and stator to effect proper radial alignment therebetween, and a rocker arm mechanism was employed to maintain the rotatable assembly and stator in their proper assembled positions while an adhesive such as thermosetting resin, was applied to band together the stator and opposite end plates in which the rotatable assembly was journaled.
In U.S. Pat. No. 3,705,994 another method of assembling dynamoelectric machines is disclosed wherein the opposite end frames thereof were welded to beams carried by the stator while the rotatable assembly was supported therein; however, one of the disadvantageous or undesirable features of this method is believed to be that the welds themselves, upon cooling, manifestly created stresses which tend to effect misalignment, as well known to the art.
In U.S. Pat. No. 2,892,225, there is disclosed a method of casting metal wherein molten metal in predetermined amounts are delivered directly from a source or furnace therefor to a casting ladle disposed adjacent to a mold, and the molten metal is then poured from the ladle into the mold. One of the disadvantageous or undesirable features of this past method of casting metal is believed to be that it was necessary not only to maintain the molten metal in the furnace at a predetermined temperature proper for the casting operations but it was also necessary to maintain such predetermined temperature of the molten metal as it was delivered from the source to the casting ladle. Since some metals, such as zinc, lead, aluminum or the like and various alloys thereof cool or solidify at a rather rapid rate, the time factor involved in delivering such molten metal from the source thereof to the casting ladle and casting it would, of course, be critical and relatively short.